Technical Abstract:
Introduction: Physical and chemical procedures are applied to broiler carcasses during processing to remove bacteria. It is unclear how effective different types of wash steps are in lowering the presence or numbers of pathogenic bacteria.
Purpose: The objective of this study was to measure the individual and combined effectiveness of five separate on-line wash steps applied between exsanguination and chilling in a commercial U.S. broiler processing plant.
Methods: In each of five replicate plant visits, five carcasses were collected from the shackle line directly before and after each of five separate wash steps. Sample sites included: pre-scald brush washer, post feather pick (New York dressed) spray washer, inside/outside spray washer, post-evisceration brush washer and final pre-chill spray washer. Carcasses were rinsed in PBS; rinsate was examined for numbers of Campylobacter and E. coli and presence of Salmonella using standard cultural methods. Numbers were compared using Tukey’s honest significant difference test; prevalence was compared using Kruskall-Wallis test.
Results: Overall, numbers of Campylobacter were lowered from log 2.58 to log 1.15 cfu/mL carcass rinse but the inside/outside washer was the only step that caused a significant drop by itself. Although no single wash step caused a significant decrease in E. coli or Salmonella, the five wash steps in series did lower E. coli numbers (from log 4.60 to 2.69 cfu/mL) and reduced Salmonella prevalence (from 80% to 24%).
Significance: Although, when examined in isolation, the benefit of broiler carcass wash steps may not be evident, when combined in series they are effective to lessen bacterial contamination on carcasses.